Screw



Nov. 7, 1933. w

F. FLESSELLEV'S 1,934,347

SCREW Patented Nov. 7, 1933 UNITED STATES PATENT OFFICE SCREW Warren Frederick Flesselles, Potts Point, near Sydney, New South Wales, Australia 1 Claim.

This invention relates to improvements in screws for wood or metal operable by a screwdriver.

It is well known that owing to defects in screwdrivers and the tendency of a person to turn a screwdriver other than in a purely radial manner, the screwdriver is frequently forced out of the usual transverse slot provided in the head of screws of the above kind.

An object of the present invention is to provide a screw which will obviate or minimize the above iiefects and ensure that the screw is inserted and ithdrawn in a more expeditious manner. EAccording to the invention the head of the rew which may be of the countersunk, cheese head, or other type, is provided with a slot for engagement'by a screwdriver. The slot is unlike that usually provided in that it has a central stop or abutment which is formed by displacing some of the metal adjacent to the slot and is adapted to be bridged by the operative face of the screwdriver, said screwdriver being provided with a gap receive the abutment.

The abutment divides the slot in the screw :entrally, and by engagement with the gap prorided in the screwdriver blade tends to prevent .ateral movement thereof with respect to the ;crew, with the result that the tendency of the )lade to leave the said slot is eliminated.

In order that the invention may be more readly understood reference will now be made to the accompanying drawing wherein:-

Figure 1 is a plan view of my improved screw :howing the central abutment.

Figure 2 is an elevational view of the head of Figures 5 and 6 illustrate the preferred method adopted for forming the abutment across the slot in the screw. Figure 5 shows a die preparatory to descending upon the head of the screw and Figure 6 shows the head of the screw after the die has descended, and forced some of the metal of which the head is composed, into the slot to form the abutment.

The slot '7 for engagement by the screwdriver may be formed by milling or stamping in the usual manner after which operation it is necessary to produce the abutment 8 centrally of the slot 7.

I have found that the most convenient manner of forming the abutment is to displace'into the slot '7 some of the-metal, from the head 9 of the screw.

The abutment 8 as seen in Figure 3 is formed by two portions or lugs 10 of metal which have been pressed into the slot 7 by means of a die such as that diagrammatically represented at 11 in Figures 5 and 6. The die 11 leaves a space 12 in the head of the screw the depth of which is less than the depth of the slot 7.

Having determined upon the size of the abutment 8, the length and width of the die 11 and the extent to which it is forced into the head of the screw, can easily be determined by calculating the volume of metal desired to form the abutment 8.

The screwdriver used with the present invention will require to have a gap such as that indicated at 13 in Figure 4.

I claim:

A screw comprising a threaded stem, a slotted head integral therewith and provided with a top face, and a narrow abutment formed in the slot in said head and constituted by two narrow projections disposed centrally in and transversely of said slot, said projections beihg spaced from the top face of the screw head and in the direction of the bottom of the slot, and consisting of equal portions of metal forced from the opposed walls of said slot. 

